Methylbenzenes, side-chain oxidation

Side chain oxidation of methylbenzenes has been developed into a route for the... 

In the case of methylbenzenes, oxidation of the side chain can be interrupted by trapping the aldehyde in the form of a non-oxidizable derivative, the gem-diacetate (Latin Gemini, twins), which is isolated and then hydrolyzed. 

Cobalt(III) acetate oxidizes thianthrene and 9,10-diphenyl-anthracene in acetic or trifluoroacetic acid to the cation radicals, as shown by esr (Heiba et al., 1969b). In flow systems, Co(III) acetate in trifluoroacetic acid has also given well-resolved esr spectra of polyalkylbenzene cation radicals (hexa-, penta-, and all tetra-methylbenzenes, 1,3,5-tri-t-butyl-, and 1,4-di-t-butylbenzene) which are difficult to make in other ways (Dessau et al., 1970). When similar oxidations of alkylaromatics are carried out in static systems, further reactions occur, and these are sometimes of preparative value, since among the products are nuclear and side chain acetates. The reactions have been clarified most recently by the work of Heiba and Dessau. 

---